A major clinical problem relating to surgical repair or inflammatory disease is adhesion which occurs during the initial phases of the healing process after surgery or disease. Adhesion is a condition which involves the formation of abnormal tissue linkages. These linkages which form can impair bodily function, produce infertility, obstruct the intestines and other portions of the gastrointestinal tract (bowel obstruction) and produce general discomfort, e.g. pelvic pain. The condition can be life threatening. The most common form of adhesion occurs after surgery as a result of trauma, although adhesion may occur as a result of other processes or events such as pelvic inflammatory disease, mechanical injury, radiation treatment and the presence of foreign material.
Various attempts have been made to prevent postoperative adhesions. For example, the use of peritoneal lavage, heparinized solutions, procoagulants, modification of surgical techniques such as the use of microscopic or laparoscopic surgical techniques, the elimination of talc from surgical gloves, the use of smaller sutures and the use of physical barriers (films, gels or solutions) aiming to minimize apposition of serosal surfaces, have all been attempted. Unfortunately, very limited success has been seen with these methods. Barrier materials, in various forms such as films and viscous intraperitoneal solutions, which are designed to limit tissue apposition, have also met with only limited success. The best of these barrier materials include cellulosic barriers, polytetrafluoroethylene materials, and dextran solutions. Also, a number of films based on polylactic acid, polyglycolic acid and copolymers of the two have proven to be unsuccessful. Indeed, most barrier materials have met with failure because these materials can induce untoward biological effects, e.g., foreign body reaction.
U.S. Pat. No. 5,410,016 to Hubbell, et al. is directed to photopolymerizable biodegradable gels for use as adhesion barriers, as control release systems for drugs, to provide temporary protection of tissue surfaces and for adhering or sealing tissues together. Hubbell, et al. discloses water-soluble macromonomers containing photopolymerizable groups on each end which are administered or placed on tissues prior to a photopolymerization step. After administration, the macromonomers are photopolymerized in situ in order to produce a crosslinked polymer on the tissue. The method of Hubbell, et al. suffers from the disadvantage that it is a cumbersome system, requiring additional equipment and expertise which adds to the cost of the treatment. In addition, the method suffers from the disadvantage that the patient must be irradiated with energy to polymerize the macromonomers during or after surgery, potentially compromising sterility and complicating and prolonging the surgical process. Given the nature of the system used to polymerize macromonomers, the Hubbel system produces polymers of high crosslink density which are somewhat weak in structure. In contrast to the polymers of Hubbell, the present invention makes use of polymers which are polymerized prior to use in the patient ("prepolymerized").
Ideally, a physical barrier for adhesion prevention should be completely absorbable and nonreactive. In addition, it should stay in place in the body with a minimum of suturing or stapling.